feat(agent): SIGHUP 重读节点本地配置并热重渲染,不踢在线用户

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/cmd/agent/main.go

@@ -44,6 +44,23 @@ func main() {
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer stop()
 
+	// SIGHUP 重读节点本地配置(acl.json / warp.json)并重渲染。走 sing-box 的 SIGHUP
+	// 热重载路径,在线用户不掉线;重启 agent 则会冷启 sing-box,把所有人踢下线。
+	hup := make(chan os.Signal, 1)
+	signal.Notify(hup, syscall.SIGHUP)
+	defer signal.Stop(hup)
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-hup:
+				log.Printf("[pangolin-agent] SIGHUP: re-reading node-local config (acl.json/warp.json)")
+				agent.SingBox().Refresh()
+			}
+		}
+	}()
+
 	log.Printf("[pangolin-agent] starting (control-plane=%s, version=%s)", cfg.ControlPlaneAddr, cfg.AgentVersion)
 	start := time.Now()
 	if err := agent.Run(ctx); err != nil {

server/internal/agentd/acl_test.go

@@ -1,12 +1,14 @@
 package agentd
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
 
 	agentv1 "github.com/wangjia/pangolin/server/internal/pb/agentv1"
 )
@@ -439,6 +441,32 @@ func TestACL_DeletedFileKeepsInMemoryLastGood(t *testing.T) {
 	}
 }
 
+// Refresh() 必须能触发一次重渲染(经 debounce 循环),用于「编辑 acl.json 后
+// systemctl reload pangolin-agent」而不必重启 agent(重启会冷启 sing-box 踢人)。
+func TestSingBoxRefresh_TriggersRender(t *testing.T) {
+	cfg := testConfig(t)
+	writeACL(t, cfg.ACLConfigPath, validACL)
+	fr := &fakeRestarter{}
+	sb := NewSingBox(cfg, fr)
+	sb.ApplyConfig(sampleSnapshot(&agentv1.Credential{DpUUID: "aaaa", Protocol: agentv1.ProtocolBoth}), true)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	go sb.Run(ctx)
+
+	// 等首次渲染落地(ApplyConfig 已 markDirty)
+	eventually(t, 2*time.Second, func() bool {
+		_, err := os.Stat(cfg.SingboxConfigPath)
+		return err == nil
+	}, "首次渲染写出配置")
+
+	// 断言 reloadCount 而非 count:首次渲染已冷启动过(started=true),此后的重渲染
+	// 一律走 Reload(SIGHUP 热重载),Restart 计数不会再增加。断言错计数器会假失败。
+	before := fr.reloadCount()
+	sb.Refresh()
+	eventually(t, 2*time.Second, func() bool { return fr.reloadCount() > before }, "Refresh 触发了热重载")
+}
+
 // 新 agent 实例(模拟进程重启) + 被删的 acl.json → 磁盘 last-good 兜底,规则仍在。
 func TestACL_ColdStartAfterDeletedFileFallsBackToDisk(t *testing.T) {
 	cfg := testConfig(t)

server/internal/agentd/singbox.go

@@ -446,6 +446,11 @@ func (s *SingBox) markDirty() {
 	}
 }
 
+// Refresh 请求一次重渲染。供 agent 收到 SIGHUP 时调用,使编辑节点本地配置文件
+// (acl.json / warp.json)后无需重启进程即可生效 —— 重启 agent 会让 sing-box 走
+// 冷启动(Restart),把全部在线用户踢下线。
+func (s *SingBox) Refresh() { s.markDirty() }
+
 // Run drives the debounce loop: it coalesces bursts of changes within
 // DebounceWindow into a single write+restart. It blocks until ctx is cancelled.
 func (s *SingBox) Run(ctx context.Context) {